Laser cutter mode configuration using M452

I have one of the Classic Blue and White 60W Chinese laser cutter/engraver.
The Chinese controller board eventually failed and I decided to upgrade it with one of my Duet 0.6 boards.
I have had some success with the Fan0 output via the M571 code, but I would like to investigate the RepRapFirmware using the Laser mode as described on the gcode for Duet3d wiki page.

I have would like the following functionality X axis, Y axis, an enable pin (FAN0-) along with a correctly configured PWM pin not sure which one yet, maybe a heater.

So I have a standard setup for cartesian XY motion with endstops and a diode from FAN0- to laser PSU IN pin.
This has been proved to work with M571 style configuration.

So, I want to use the following to allow the FAN0- pin to be used as an enable.

No I was hoping that once I had the vector stuff going I could work out how to PWM the heater0 output and then use that to vary the power to the laser. At least that would then give me the ability to cut and engrave at different power levels.

To engrave bitmaps would need some sort of work flow that will enable me to move the head at a fixed speed and vary the heater0 PWM as the head is moving, or just do lots of small movements at different power levels, "that would just be messy".

My work flow for cutting and vector engraving uses Fusion 360 CAM with a gcode plugin, I expect to have to program a new plugin based on the one I am using to optimise the gcode output to the Duets gcode.